Add warning message that this software is deprecrated

[toothbrushes]

I believe I just bricked my device (not sure how else to recover it other than JTAG):
Proxmark/proxmark3#994

It would be very helpful to others that follow if a warning message was displayed to use this instead:
https://github.com/RfidResearchGroup/homebrew-proxmark3

Or even just remove this tap since I don't think anyone will be using it